It's all in the genes...or is it?

BHA Director of Equine Science & Welfare Tim Morris on mapping of genes in racehorses

There has been a long debate on nature versus nurture; do the characterises of a living thing stem from how it’s made or from the environment in which it exists? The discovery of the principles of how traits are passed to offspring (heredity), and then the actual mechanism (via genes) might have given the nature side of the argument the upper hand.

However, consider two identical twins separated at birth, one bought up on Dover and one in Calais and then reunited at an age of twenty. With different languages, culture, religion, nutrition, and sports involvement who would like to say they really are identical twins and that it is all down to their genes?

So what should we make of the 'discovery' of the 'speed gene' in racehorses? Let’s take a step back and explain some of the key concepts, how it is that we can study them, and why we should do.

Take a look at this leaflet that summarises a British Horseracing project to look at the association of genes and disease. It defines some key terms, explains how the mapping of all horse genes now allows us to see which are associated with disease, and then what diseases are being studied.

Unlike the Irish research into the association between genes and performance, the British, and other, research focuses on disease.

Why is this? The first is an understandable conservatism, a healthy concern for unforeseen consequences. There are examples of how excessive selection for a small number of traits can lead to considerable problems.

The second is a wider concern in thoroughbred breeding that a particular science or technology should not be concrecentrated in the hands of a few, whether by patent protection or financial clout; hardly the basis for a broad based and exciting crop of racehorses.

Finally there is the recognition that an unhealthy horse cannot be a fast horse, and that disease is also bad welfare.

The British Horseracing project to look at the association of genes and disease has now finished, and it is being reported and scientifically assessed this year under the auspices of the veterinary research function of the Horserace Betting Levy Board. So watch this space.

One big question that is now being faced by all the research into the association between genes and disease, or speed, or whatever, is whether it’s is likely to work? Will we find what genes cause speed or disease? At present, despite high initial hopes, there is a growing scepticism that it easily will. So far despite some massive funding into human disease, many traits are proving remarkably resistant to full genetic definition.

Does this means that genes are less relevant? No, but that what appears a simple code is actually far more complex, and prone to variations in expression, including those resulting from environmental interactions.

So the nature versus nurture debate is not dead, genes are important, but don’t (yet?) bet your savings on a horse’s genetic profile!